Those who smoke while expecting a baby increase the risk of their child being born with a serious malformation by as much as 50%, the study found. The disclosure led to calls for new measures to reduce what the authors called "staggeringly high" levels of smoking among pregnant women, informs The Guardian.

Congenital heart disease is also distinctly associated with moms who smoke. Researchers had long suspected that was the case, but the extensive review process revealed papers that corroborate the connection. Both oral clefts and congenital heart disease are treatable, but heart disease is far trickier to address. Children who need complicated, costly surgery must spend considerable time in the hospital, and not all cases can be fully corrected, says TIME.

Every year in England and Wales around 3,700 babies in total are born with such a condition.

The experts base their calculations on 172 research papers published over the last 50 years, which looked at maternal smoking and birth defects. The findings, from 174,000 cases of malformation and 11.7 million healthy births, revealed that smoking increased the risk of many abnormalities.

The chance of a baby being born with missing or deformed limbs is 26% higher, and cleft lip or palate is 28% more likely, according to BBC News.